diff --git a/pkg/apis/networking/validation/validation.go b/pkg/apis/networking/validation/validation.go
index 48776ee4193..266348ea070 100644
--- a/pkg/apis/networking/validation/validation.go
+++ b/pkg/apis/networking/validation/validation.go
@@ -68,8 +68,13 @@ func ValidateNetworkPolicyPort(port *networking.NetworkPolicyPort, portPath *fie
 			for _, msg := range validation.IsValidPortNum(int(port.Port.IntVal)) {
 				allErrs = append(allErrs, field.Invalid(portPath.Child("port"), port.Port.IntVal, msg))
 			}
-			if port.EndPort != nil && *port.EndPort < port.Port.IntVal {
-				allErrs = append(allErrs, field.Invalid(portPath.Child("endPort"), port.Port.IntVal, "must be greater than or equal to `port`"))
+			if port.EndPort != nil {
+				if *port.EndPort < port.Port.IntVal {
+					allErrs = append(allErrs, field.Invalid(portPath.Child("endPort"), port.Port.IntVal, "must be greater than or equal to `port`"))
+				}
+				for _, msg := range validation.IsValidPortNum(int(*port.EndPort)) {
+					allErrs = append(allErrs, field.Invalid(portPath.Child("endPort"), *port.EndPort, msg))
+				}
 			}
 		} else {
 			if port.EndPort != nil {
diff --git a/pkg/apis/networking/validation/validation_test.go b/pkg/apis/networking/validation/validation_test.go
index fdb6a00fa43..c03fd0af1ee 100644
--- a/pkg/apis/networking/validation/validation_test.go
+++ b/pkg/apis/networking/validation/validation_test.go
@@ -1018,6 +1018,32 @@ func TestValidateNetworkPolicy(t *testing.T) {
 				},
 			},
 		},
+		"invalid endport range defined": {
+			ObjectMeta: metav1.ObjectMeta{Name: "foo", Namespace: "bar"},
+			Spec: networking.NetworkPolicySpec{
+				PodSelector: metav1.LabelSelector{
+					MatchLabels: map[string]string{"a": "b"},
+				},
+				Egress: []networking.NetworkPolicyEgressRule{
+					{
+						To: []networking.NetworkPolicyPeer{
+							{
+								NamespaceSelector: &metav1.LabelSelector{
+									MatchLabels: map[string]string{"c": "d"},
+								},
+							},
+						},
+						Ports: []networking.NetworkPolicyPort{
+							{
+								Protocol: nil,
+								Port:     &intstr.IntOrString{Type: intstr.Int, IntVal: 30000},
+								EndPort:  utilpointer.Int32Ptr(65537),
+							},
+						},
+					},
+				},
+			},
+		},
 	}
 
 	// Error cases are not expected to pass validation.